Oil tanker



Nov. 11 1969 AKIO HAYAMA 3,477,401

OIL TANKER Filed May 6, 1968 ATTORNEYS United States Patent Int. Cl.B63b 25/12,- B63g 8/00 US. Cl. 114-74 1 Claim ABSTRACT OF THE DISCLOSUREThe tanker has a hull, an air tight and water pressure resistant bridgeportion on said hull, ballast tanks and a water tight engine space insaid hull having a propulsion engine therein. The hull has a pluralityofcompartments therein, the lower portion of each compartment being airtight and the upper part having holes therein. A flexible bag isprovided in each compartment having the edges thereof secured in airtight engagement with the Walls of the compartment between the upper andlower portions thereof, and an oil inlet and discharge means is providedin the lower portion of each compartment for feeding and withdrawing oilfrom within the bag in the lower portion of the compartment.

The present invention relates to an oil tanker which is equipped with asea water compartment having therein an oil tank of variable capacity.

In order to improve the economy of shipping in ships, there is a strongtendency to make ships larger, faster and more specialized. In thestructure of a ship, too, various ways have been developed in order toeliminate wave resistance and induced drag (induction effect).

The present invention aims at obtaining the same effect for a submarinein respects of resistance and waves.

The oil tanker constructed in accordance with the present invention hasvarious operational equipment similar to that of a submarine includingan air-tight bridge house which has periscopes, snorkel equipment and aresidential area in order to maintain sufiicient watch and communicationwhen the main body of the ship goes under water; an engine room;sea-water inducing and discharging equipment for the main ballast tankswhich can be remote controlled from the bridge house when the shipsubmerges or surfaces; an automatic control system in which anunderwater navigation helm, a horizontal helm and avertical helm can beoperated by electro-hydraulic valves; buoyancy; an automatic controlsystem for trim adjustment.

The invention will now be described in connection with the accompanyingdrawings in which:

FIG. 1 is an elevation view of the main body of the oil tanker, into theopenings of which outside water pressure can be induced;

FIG. 2 is a section at A-A line of FIG. 1 and show ing the situation inwhich no oil is loaded in the tanker and a pressure-resisting bag is ina position along the ships bottom and the main body of the shipsubmerges full of sea water in its cargo compartments and the oil tankof variable capacity is unformed;

FIG. 3 is a similar view showing the situation in which oil is presentin the cargo compartments, the pressureresisting bag is pushed upward,the oil tank of a variable capacity is filled with oil and the body ofthe ship is submerged;

FIG. 4 is a partial perspective view partly in section showing how thepressure-resisting bag is fixed onto the walls of the cargo compartmentsand showing a flexible air exhaust tube passing through thepressure-resisting bag.

3,477,401 Patented Nov. 11, 1969 The amount of pressure has no relationto the direction in which it works. Similarly, water pressure is a forcewhich works upon a unit area and its c.g.s. unit is g./cm./sec.dyne/cmF. In oceanography, 10 dyne/ cm. 1 dembal (db) is used as a unit.Water pressure in creases in accordance with the increase in depth. Whensetting a Z shaft as being right downward, water pressure at a certaindepth is expressed as follows.

11 P=f Dgdz In this formula, P is density and g is acceleration ofgravity. As this formula shows, water pressure increases by about 1atmospheric pressure when the depth of water increases by 10 m. Thus, inorder to construct a ship similar to a submarine, it is required toprovide an airtight hull structure which is strong enough to withstandwater pressure.

In the present invention, the bridge house containing a residential areaand the engine room are made air-tight and the hull containing the cargocompartments has many small holes in the upper portion thereof coveredby screens so that sea-water can flow into the partitioned compartments.The lower portion of each compartment is airtight. A flexible,water-proof and pressure-resisting bag, which is made of a textile sheetof strong fibre such as neoprene reinforced nylon or a rubber sheet, isprepared in a shape suitable for each of these partitioned compartmentsand as shown in FIG. 4 the cylindrical head on each edge of the bag isfixed onto the walls of each compartment by a molding 3 positionedbetween the upper and lower portions of the compartments. An air-exhausttube 4 which is connected with a vacuum pump is passed through the bagat an appropriate place. Thus, an oil tank of variable capacity isformed between the ships bottom and the bag 1. An oil pipe 13 forloading and unloading or oil is provided at the ships bottom and is tobe connected with an oil pump.

In the present invention, in order to keep the gravity of the floatingbody in the lower part of the main body 9 of the ship when it isunloaded, sea water is placed into some part of the compartment for trimadjustment. By this means together with the use of the main ballasttanks, it is possible to stabilize the ship when it is afloat.

When the ship leaves port unloaded for the purpose of loading oil, thebag 1 of each oil tank 14 of variable capacity from which the air hasbeen exhausted by the vacuum pump takes a position in which it coversthe bottom of the tank as shown in FIG. 2, and sea water 15 comingthrough a water inlet 5 fills each compartment 2. Due to this and alsodue to the balancing effect of the main ballast tanks 17, the main body9 of the ship submerges below water level WL and at a depth of 5 m. to10 m. leaving a part of the air-tight bridge house 7 exposed above thewater surface. Thus, the ship navigates under water to a port ofdestination watching its route by a periscope 6.

Air supply and exhaust for the bridge house 7 and the engine room isdone by snorkel equipment 10. A main engine 11 can be operated either byhand or by remote control. Sea water 15 is allowed to flow into thecompartments 2, so that all the other parts of the main body of the shipexcepting the air-tight structure are free from the influence of waterpressure and the ship is quite safe in spite of the increase of about 1atmospheric pressure at a depth of about 10 in.

When the ship arrives at a port of destination and starts loading ofoil, the oil stored in a tank either on the ground or on the sea issupplied to the ship through the oil pipe 13 which is fixed on the shipsbottom. Then, the bag 1 is pushed upward with the inflow of oil and thecapacity of the oil tank keeps expanding; while, the sea water 15 in thecompartment 2 is gradually discharged because the supplying pressure ofthe oil pump is over 1 atmospheric pressure. When the tank capacity hasreached to the maximum, there remains almost no sea Water in thecompartment 2. In the oil tank 14 of variable capacity formed by thepressure-resisting bag, it may happen sometimes that air-pockets areproduced when oil is supplied by the air pump and that they get togetherto form a mass of air. But, they can be taken out by appropriateoperation of the vacuum pump. This contributes to the supplement ofwater pressure resisting strength and to trim adjustment.

When loading ends, the ship leaves for the home port navigating underwater at a constant depth of 5 m. to m. i.e. the depth at which the mainbody of the ship receives little influence of waves, resistance andwater pressure.

During navigation or at the time of temporary anchoring, it is easy forthe ship to operate similar to a submarine such as surfacing the mainbody by blowing the main ballast tank appropriately.

Generally, from a structural point of view, an oil tanker has adisadvantage that explosion or fire occurs easily. That is to say, evenwhen a ship is unloaded, there may remain some amount of oil in thecompartments, due to which evaporated gas is easily generated and staysin the compartment. When the ship is fully loaded, the contact betweenthe surface of oil and the air causes the evaporated gas to stay there.Especially, when the ship navigates in an area of high temperature,generation of evaporated gas is great due to the abovementioned reasonand also due to the rolling motion of the ships body.

In the present invention, however, no evaporated gas is generated in thecompartments as oil is not loaded directly into the compartments.Further, whether oil is loaded in the oil tank of variable capacity ornot, no air is present in the tank and consequently evaporated gas isnot generated and there is little danger of explosion or fire.

As described above, the oil tanker constructed in accordance with thepresent invention has the advantage that it can navigate under waterwithout much resistance at a high speed with small horsepower andthereby it has great mobility and a high rate of operation. Anotheradvantage is that it does not need a completely airtight hull structurewhich is normally indispensable for a submarine and therefore the costof construction is reduced substantially.

It is of course possible to carry out changes in design provided such achange does not deviate from the purpose of the present invention.

What I claim as my invention is:

1. An oil tanker, comprising a hull, an air tight and water pressureresistant bridge portion on said hull, ballast tanks and a water tightengine space in said hull having a propulsion engine therein, and saidhull having a plurality of compartments therein, the lower portion ofeach compartment being air tight and the upper part having holestherein, a flexible bag in each compartment having the edges thereofsecured in air tight engagement with the walls of the compartmentbetween the upper and lower portions thereof, and oil inlet anddischarge means in the lower portion of each compartment for feeding andwithdrawing oil from within the bag in the lower portion of thecompartment.

References Cited UNITED STATES PATENTS TRYGVE M. BLIX, Primary ExaminerUS. Cl. X.R.

